Electric-alarm try-cock.



No. 642,9l3. Patented Feb. 6, I900. S. M. MATHEWS.

ELECTRIC ALARM TRY (Appl t n fil dAp COCK.

(In Model.)

UNITED STATES PATENT Orricn.

STEPHEN M. MATHEWS, OF TORONTO, CANADA.

ELECTRIC-ALARM TRY-COCK.

SPECIFICATION forming part of Letters Patent No. 642,913, dated February 6, 1900.

Application filed A i114,1899. Serial No. 713,071. (No model.)

To all whom it may concern:

Be it known that I, STEPHEN M. Mnrnnws, a subject of the Queen of Great Britain, residing in the city of Toronto, in the county of York, and Province of Ontario, Canada, have invented certain new and useful Improvements in Electric-Alarm Try-Cocks; and I hereby declare that the following is a full, clear, and exact description of the same.

This invention relates to certain new and useful improvements in electric alarms for steam-generating boilers, and it relates more particularly to its peculiar construction and arrangement and its relative position to the water-line of the boiler, the object of the invention being to so arrange the apparatus that it will instantaneously sound an alarm when the water in the boiler has fallen below a predetermined level; and the invention consists, essentially, of providing the try-cock with an expansion -chamber in communication with either the water-column ot' the boiler or with the boiler itself, a hermetically-sealed air-chamber contiguous to the expansionchamber, a diaphragm actuated by the air within the hermetically-sealed air-chamber, and an adjustable contact-screw in circuit with the battery and alarm, through which the circuit is completed when the air in the hermetically-sealed chamber is expanded to move the diaphragm into contact with the point of the contact-screw, as hereinafter more fully set forth, and more particularly pointed out in the claims.

In the drawings, Figure l is a sectional view of the apparatus. Fig. 2 is an enlarged sectional view of the upper part of the apparatus, showing the air-chamber, diaphragm, and contact-screw. Fig. 3 is a plan view of the top of the same.

A represents the shell of the apparatus, one end of which is provided with an integrallyformed concavo-convex end a and the other end of which is provided with a screw-threaded stem a to be fitted into the boiler or water-colner side of the end a.

apparatus is in position, is fitted into the water-column or boiler and the water or steam passes from the boiler or water column through the opening Z) of the stem a into the chamber B. By means of the drain-cock O the contents of the chamber B can be permitted to escape by opening its valve.

The end of the shell A is provided with a dome S, between which and the concaved end of the shell is formed an air-chamber. Located centrally between the dome and the concaved end of the shell is a diaphragm D, the side face of which is opposed to the concaved end a, and which is made of electrically-conducting metal.

H represents a post provided with a sore threaded stem h, fitted through the top of the dome S, and interposed between the screwt-hreaded stem 7L and the dome S is an insulated washer G to prevent electrical contact between the post and the dome. Passing through the post H is an adjustable contactscrew J, provided with a lock-nut 1, adapted to bear against the top of the binding-post,

the lower end of which is adapted to be engaged by the diaphragm D when actuated by the expansion of the air in the chamber 0, formed between the diaphragm and the concaved end of the shell.

M represents an opening from the chamber T between the diaphragm D and dome to allow of the exit of the air from the chamber when the diaphragm is actuated.

Formed through the shellA into the chamher 0 is an opening fitted with a screw N, by means of which the air can be admitted to the chamber. In order to provide a means of access to the chamber T and diaphragm through the dome, the dome is provided with an en larged opening fitted with a nut R, the shank of which is screwed into the opening, which is provided with a central bore to receive the insulated washer G, through which passes the stem of the post H, the inner end of the post being locked to the washer by means of a nut, and the outer part of which is provided with a shoulder resting against the outer part of the washer. The post His provided with an extension L to receive the circuit-wire, and the extension L is provided with a set-screw for locking the wire to the extension L of the post H.

The use of theinvention is as follows: The

stem a of the shell Ais screwed into the boiler or Water-column slightly below the water-line. \Vhen the water in the boileror Water-column is at its normal level-that is, at the level of the water-lineit will pass through the opening 1) in the stem at to the chamber B and prevents the passage of the steam from the boiler to the chamber. The contact-screw is adjusted so thatit will not engage the diaphragm until the temperature in the chamber B has risen above 212 Fahrenheit, which is the sensible temperature of boiling water. When the water in the boiler or water-column has fallen below the Water-line, the Water will drain from the chamber B back into the boiler or water-column and allow of the passage of the steam from the boiler or water-column into the chamber B, and as the steam is al ways under pressure in agenerating-boiler it will increase the temperature of the chamber above 212, raising the temperature of the air in the closed chamber 0 to the same point and cause the movement of the diaphragm toward the point of the contact-screw, ground ing the current bymeans of the contact-screw and the remaining parts of the apparatus, completing the circuit of the currentthrough the wire F to the electric bell in any ordinary manner. 1 Having thus fully described my invention, what I claim as new, and desire to secure by Letters Patent, is-

1. An electric-alarm try-cock consisting of an expansion-ehamber communicating with the Water-column or boiler, a Cono'aVO-OOntex end for the expansion-chamber, adiaphragm opposed to the concave-convex end, adapted to form between itself and the said end of the chamber a hermetically-sealed air-chamber, a supplemental end for the expansion-chamber inclosing the diaphragm, an insulated post passing through the supplemental end, a contact-screw passing through the post, the point of which is adapted to be engaged by the diaphragm when actuated by the expansion of the air Within the hermetically-sealed air-chamber to complete the circuit to the alarm, substantially as specified.

2. An electric-alarm try-cock consisting of an expansion-chamber communicating with the water-column or boiler, a concavo-eonvex end for the expansion-chamber, a diaphragm opposed to the concavo-conveX end, adapted to form between itself and the said end of the chamber a hermetically-sealed airchamber, a supplemental end for the expansion-chamber inclcsing the diaphragm, an insulated post passingthrough the supplemental end, a contact-screw in circuit with the alarm passing through the post, the point of which is adapted to be engaged by the diaphragm when actuated by the expansion of the air within the hermetically-sealed airchamber, Which is provided with an opening between the diaphragm and supplemental end to allow of the escape of the airfrom within it, substantially as specified.

STEPHEN M. MATHEWS.

VJitn esses:

G. M. GARDNER, M. J. KNOX. 

